package com.ianmoone.JZOF;

import java.util.HashSet;
import java.util.Scanner;

public class HuaWei1 {
	public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        String str = in.nextLine();
        func(str);
    }
	public static void  func(String str){
		char[] charArray = str.toCharArray();
		HashSet<Character> set = new HashSet<>();
		StringBuffer stringBuffer = new StringBuffer();
		int size = 0;
		for (int i = 0; i < charArray.length; i++) {
			size = set.size();
			set.add(charArray[i]);
			if (size!=set.size() ) {
				stringBuffer.append(charArray[i]);
			}
		}
		System.out.println(stringBuffer);
		
	}
}
